this video about ticks on humans, is not bad. basically she says to cover up and use any oil ideally scented with something strong, on exposed skin. to stop them seeing/smelling you as a walking blood sack.
http://www.ehow.com/video_4951483_repel-ticks-humans.html
http://www.ehow.com/video_4951483_repel-ticks-humans.html